| 5 |
| 5 |
| 5 |
当PF2⊥x轴时,P的横坐标为
| 5 |
| 4 |
| 3 |
| |PF1| |
| |PF2| |
2a−
| ||
|
6−
| ||
|
| 7 |
| 2 |
当PF1⊥PF2 时,设|PF2|=m,则|PF1|=2a-m=6-m,3>m>0,由勾股定理可得
4c2=m2+(6-m)2,即 20=2 m2-12 m+36,解得 m=2 或 m=4(舍去),
故
| |PF1| |
| |PF2| |
| 6−2 |
| 2 |
综上,
| |PF1| |
| |PF2| |
| 7 |
| 2 |
| x2 |
| 9 |
| y2 |
| 4 |
| |PF1| |
| |PF2| |
| 5 |
| 5 |
| 5 |
| 5 |
| 4 |
| 3 |
| |PF1| |
| |PF2| |
2a−
| ||
|
6−
| ||
|
| 7 |
| 2 |
| |PF1| |
| |PF2| |
| 6−2 |
| 2 |
| |PF1| |
| |PF2| |
| 7 |
| 2 |